Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe Revision: 12/06

Transcription

1 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe Revision: 12/06 Copyright Campbell Scientific, Inc.

2 Warranty and Assistance The CS512 OXYGUARD TYPE III DISSOLVED OXYGEN PROBE is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products. The customer shall assume all costs of removing, reinstalling, and shipping defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will return such products by surface carrier prepaid. This warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products which have been subjected to modification, misuse, neglect, accidents of nature, or shipping damage. This warranty is in lieu of all other warranties, expressed or implied, including warranties of merchantability or fitness for a particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special, indirect, incidental, or consequential damages. Products may not be returned without prior authorization. The following contact information is for US and International customers residing in countries served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs for customers within their territories. Please visit to determine which Campbell Scientific company serves your country. To obtain a Returned Materials Authorization (RMA), contact CAMPBELL SCIENTIFIC, INC., phone (435) After an applications engineer determines the nature of the problem, an RMA number will be issued. Please write this number clearly on the outside of the shipping container. CAMPBELL SCIENTIFIC's shipping address is: CAMPBELL SCIENTIFIC, INC. RMA# 815 West 1800 North Logan, Utah CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

3 CS512 Table of Contents PDF viewers note: These page numbers refer to the printed version of this document. Use the Adobe Acrobat bookmarks tab for links to specific sections. 1. General Information Specifications Optional Probe Accessories Optional Agitator Application Information Wiring Programming Calibration Maintenance Agitator Control...7 Appendix A. Dissolved Oxygen in Fresh Water Table... A-1 Figures Table 1-1. CS Preventing Bio-fouling of the CS CS512 with PT4 Agitator Agitator Wiring Sensor Wiring...4 i

4 CS512 Table of Contents Examples 1. Sample Program using P Sample Program using P Sample Program using VoltSE Sample Program using VoltDiff Sample Program using VoltSE Sample Program using P Sample Program using Expression Sample Program using P86 and P22 Instructions Sample Program using Portset Sample Program using Portset... 8 ii

5 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe An accurate and reliable sensor is a critical element in any measurement system. The Oxyguard Stationary Probe meets these criteria for the measurement of dissolved oxygen. 1. General Information The Oxyguard Stationary Probe is a galvanic probe which produces a millivolt signal proportional to the amount of oxygen present in the measured medium. Oxygen diffuses through the membrane onto the cathode, reacts chemically, and combines with the anode. An electrical current is produced by this chemical reaction which is converted from microamps to millivolts by an in-line resistor. An in-line thermistor also conditions the signal providing automatic temperature compensation. With these features, the probe produces a millivolt output proportional to the oxygen present in the medium in which it is placed. The probe consists of two parts, an upper part with cathode, anode and cable, and a lower part comprising a screw on membrane cap with fitted membrane. The cap is filled with electrolyte and simply screwed onto the top component. The probe is self-polarizing and requires no external power source. There are two wires to connect. Because the probe's output is linear, it is possible to connect it directly to a data acquisition system capable of handling the small millivolt signal. The probe's robust construction and simple design make maintenance and servicing it straightforward. There is no need to send the probe back to the factory for servicing. It utilizes a strong, easy-to-clean and easy-to-change membrane in a screw-on membrane cap. Regular servicing is not required. When necessary the probe can be fully overhauled in five minutes. FIGURE 1-1. CS512 1

6 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe 2. Specifications Principle of Measurement: Membrane covered galvanic oxygen probe Output Signal: 2.5 to 5 mv per mg 1-1 Repeatability: Output Impedance: Response Time: Materials of Construction: Probe body: O-rings: Membrane: Dimensions and Weight: Cable: Operating Conditions: Temperature Pressure: Minimum Submersion Depth: Minimum Water Flow: Calibration: Temperature Compensation: Range of Dissolved Oxygen: Ships with: Better than ±0.2 mg/l calibration temperature equals measuring temperature ±5 C 1 kohm After equilibration, 1 minute for 95% of final value Delrin Membrane O-ring = Buna N Body Seal O-ring = Viton 0.05 mm (2 mil) Teflon 2.28 diameter x 2.3 height 15.9 oz. standard length 7 m (23 ft); other lengths available upon request 2-wire 22 awg shielded, PVC jacketed 0 to 40 C (32 to 122 F) 0 to 29 psig 60 mm (2 ½ in) 1 cm/s (.39 in/sec) across membrane In air or in air saturated water Automatic from 4-40 C ( F) 0-20 mg/l, 0-200% Sat 5 spare membranes with O-rings 50 ml electrolyte cathode cleaning pad 2

7 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe 3. Optional Probe Accessories 4. Optional Agitator PT4-L Agitator for stagnant conditions DO electrolyte, 1 liter Membrane kit, 10 membranes The PT4 Agitator is a reliable and robust agitator for use in conjunction with probes subjected to bio-fouling in ponds and stagnant water conditions. O 2 probes require a minimum water velocity across their membranes to function properly. Therefore, to measure DO in stagnant water conditions, it is necessary to move the water past the membrane to get accurate and reliable DO measurements. In many instances the water also has a high bio-loading and the probes become fouled resulting in inaccurate DO measurements. FIGURE 4-1. Preventing Bio-fouling of the CS512 The PT4 Agitator overcomes these problems. The device is designed so that a soft bristle brush sweeps across the probe membrane or sensor tip. This sweeping action of the brush provides the required water velocity as well as prevents the membrane from becoming bio-fouled. The optimum sweeping frequency depends upon the design of probe and type of membrane used and water conditions. An ON-time of 0.25 seconds and OFF-time of 5 seconds is suitable in most circumstances. Agitator s overall size: 7-1/8" x 3-1/4" diameter, 1-1/4 lb. (180mm x 83mm, 0.6 kg) Supplied with 10 ft. (3 meters) cable. Power required: 10.5 to 18 VDC at the agitator, 1.1 amps. Maximum ON-time is 3 seconds. 3

8 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe FIGURE 4-2. CS512 with PT4 Agitator 5. Application Information Optional Repeat Cycle Timer for Agitators: Reciprocating action may be controlled by the optional solid state Repeat Cycle Timer. It sends 12 VDC pulses to the agitator coil. The ON-time is 0.25 sec. The OFF-time is adjustable from 3 to 12 sec.; requires supply voltage 10 to 17 VDC; housed in watertight cylinder 6.6" x 2" diameter (170 mm X 50 mm). NOTE SCWin users: This manual was written primarily for those whose needs are not met by SCWin. Your procedure is much simpler: just add the CS512 probe (it s in the water folder), save your program, and follow the wiring shown in Step 2 of SCWIN. 6. Wiring The CS512 probe can use one differential channel or one single-ended channel. Differential wiring is better at rejecting electrical noise and ground loop error. Colo r Whit e Functio n Signal + TABLE 6-1. Sensor Wiring CR510, CR10X, CR800, CR850, CR23X, CR1000, CR3000 Differential High, or Single-Ended Channel CR200 Series Single-Ended Channel Blue Signal - Differential Low or AG Ground 4

9 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe 7. Programming In the CR510, CR10X, and CR23X datalogger, Instruction P1 or P2 can be used. Example 1 uses a single-ended measurement for the CS512 probe; example 2 uses a differential measurement. The example measurement instructions that follow do not store data to final storage. Additional instructions (typically P92, P77, and output processing instructions such as P70) are required to store data permanently. EXAMPLE 1. Sample Program using P1 1: Volt (SE) (P1) 1: 1 Reps 2: mv 60 Hz Rejection Range ; code 23 used for CR23X 3: 1 SE Channel 4: 1 Loc [ DOmV ] 5: 1.0 Multiplier *See Calibration* 6: 0.0 Offset EXAMPLE 2. Sample Program using P2 1: Volt (Diff) (P2) 1: 1 Reps 2: mv 60 Hz Rejection Range ; code 23 used for CR23X 3: 1 DIFF Channel 4: 1 Loc [ DOmV ] 5: 1.0 Multiplier *See Calibration* 6: 0.0 Offset In the CR1000, CR800, CR850, and CR3000 dataloggers, instruction VoltDiff or VoltSE is used to measure the CS512 probe. EXAMPLE 3. Sample Program using VoltSE VoltSE (DOmV,1,mV250,1,1,0,_60Hz,1.0,0) EXAMPLE 4. Sample Program using VoltDiff VoltDiff (DOmV,1,mV250,1,True,0,_60Hz,1.0,0) VoltSE (DOmV,1,1,1.0,0) In the CR200 series dataloggers, only the instruction VoltSE is used to measure the CS512 probe. EXAMPLE 5. Sample Program using VoltSE. 5

10 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe 8. Calibration The multiplier is used to calibrate the CS512 probe. To calculate the multiplier: 1) Program the datalogger using a multiplier of one. 2) Place the OxyGuard probe in the air, shaded from the sun. Wait for readings to stabilize. This may take 15 minutes or more. 3) Determine the air temperature and barometric pressure. 4) Using a calibration chart such as that provided in the probe s manual, determine the oxygen concentration of the air. 5) Use the following equation to calculate the multiplier: M = P/R M = Multiplier P = Concentration in PPM of the air (from the calibration chart in Appendix A) R = The signal output of the OxyGuard probe when using a multiplier of one 6) Change the multiplier in the datalogger program from one to the calculated number. A more common way to enter the multiplier is to insert a separate instruction in the program. This will allow a new multiplier to be added to the program without rewriting, compiling, and downloading the program to the data logger. In the CR510, CR10X, and CR23X, use Instruction P36. The multiplier is entered into an input location called DOmult using the numeric display in PC200W, PC208W, LoggerNet, PC400, PConnect, PConnectCE, or the CR10KD. 57: Z=X*Y (P36) 1: 1 X Loc [ DOmV ] 2: 2 Y Loc [ DOmult ] 3: 3 Z Loc [ DOppm ] DOppm = DOMult * DOmV EXAMPLE 6. Sample Program using P36 In all dataloggers that use CRBasic, an expression is written. The multiplier value is entered into the expression through the Public Table using the numeric display in PC200W, LoggerNet, PC400, PConnect, and PConnectCE. EXAMPLE 7. Sample Program using Expression 6

11 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe 9. Maintenance The CS512 probe needs little maintenance. Regular cleaning of the membrane is all that is required. The membrane is very durable and can be cleaned with a cloth or soft paper. Do not scratch it clean with your fingernail. 10. Agitator Control In low flow conditions (less than about 5 cm/sec), it may be necessary to add an agitator to the CS512 probe. Campbell Scientific ships the agitator with a repeat cycle timer. Using the repeat cycle timer requires no datalogger programming. However, some users choose to use a solid state relay and have the datalogger agitate the water on the probe face either periodically throughout the day or just before measurement. Agitating just before the measurement saves on power and causes less wear and tear on the agitator and probe membrane. The wiring for the agitator as controlled by this example program would be as follows: Ground/G Datalogger 4 1 #7321 Relay Crydom D1D07 BLACK Agitator Port C1 3 2 WHITE V Battery FIGURE Agitator Wiring The following instructions would trigger the agitator as discussed in the agitator manual. In the CR510, CR10X, and CR23X, use instruction P86 and P22. 7

12 Campbell Scientific CS512 Oxyguard Type III Dissolved Oxygen Probe 45: Do (P86) 1: 41 Set Port 1 High EXAMPLE 8. Sample Program using P86 and P22 Instructions 46: Excitation with Delay (P22) 1: 1 Ex Channel 2: 20 Delay W/Ex (units = 0.01 sec) 3: 0 Delay After Ex (units = 0.01 sec) 4: 0 mv Excitation 47: Do (P86) 1: 51 Set Port 1 Low 48: End (P95) Portset (1,1) Delay(500,msec) Portset(1,0) Portset (1,1) Delay (1,500,msec) Portset (1,0) In the CR200 series dataloggers, use the Portset instruction. EXAMPLE 9. Sample Program using Portset In the CR1000, CR800, CR850, and CR3000 dataloggers, use the Portset instruction. EXAMPLE 10. Sample Program using Portset The above example is not as power efficient as possible and would require AC power to maintain a sufficient battery charge. If it is necessary to operate an agitator without AC power available, write the program so that the agitator is only operated for a short period of time just before the measurement is to be taken. 8

13 Appendix A. Dissolved Oxygen in Fresh Water Table A-1

14 Appendix A. Dissolved Oxygen in Fresh Water Table A-2

15 This is a blank page.

16 Campbell Scientific Companies Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah UNITED STATES Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA Campbell Scientific Australia Pty. Ltd. (CSA) PO Box 444 Thuringowa Central QLD 4812 AUSTRALIA Campbell Scientific do Brazil Ltda. (CSB) Rua Luisa Crapsi Orsi, 15 Butantã CEP: São Paulo SP BRAZIL Campbell Scientific Canada Corp. (CSC) th Street NW Edmonton, Alberta T5M 1W7 CANADA Campbell Scientific Ltd. (CSL) Campbell Park 80 Hathern Road Shepshed, Loughborough LE12 9GX UNITED KINGDOM Campbell Scientific Ltd. (France) Miniparc du Verger - Bat. H 1, rue de Terre Neuve - Les Ulis COURTABOEUF CEDEX FRANCE campbell.scientific@wanadoo.fr Campbell Scientific Spain, S. L. Psg. Font 14, local Barcelona SPAIN info@campbellsci.es Please visit to obtain contact information for your local US or International representative.